lib.systems: introduce toolchain, cc, and bintools attributes

lib/systems/default.nix

@@ -66,16 +66,60 @@ let
   # `parsed` is inferred from args, both because there are two options with one
   # clearly preferred, and to prevent cycles. A simpler fixed point where the RHS
   # always just used `final.*` would fail on both counts.
-  elaborate = systemOrArgs: let
+  elaborate = systemOrArgs:
+    assert lib.assertMsg (!(lib.oldestSupportedReleaseIsAtLeast 2511 && systemOrArgs ? useZig)) "The useZig attribute has been deprecated in favor of the toolchain attributes.";
+    let
     allArgs = systemToAttrs systemOrArgs;
 
     # Those two will always be derived from "config", if given, so they should NOT
     # be overridden further down with "// args".
-    args = builtins.removeAttrs allArgs [ "parsed" "system" ];
+    args = lib.pipe (builtins.removeAttrs allArgs [ "parsed" "system" ]) [
+      (lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2511 && systemOrArgs ? useLLVM) "The useLLVM attribute has been deprecated in favor of the toolchain attributes.")
+      (lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2511 && systemOrArgs ? useArocc) "The useArocc attribute has been deprecated in favor of the toolchain attributes.")
+      (lib.warnIf (lib.oldestSupportedReleaseIsAtLeast 2511 && systemOrArgs ? useZig) "The useZig attribute has been deprecated in favor of the toolchain attributes.")
+    ];
 
     # TODO: deprecate args.rustc in favour of args.rust after 23.05 is EOL.
     rust = args.rust or args.rustc or {};
 
+    toolchain = {
+      cc = if final.useLLVM || final.isDarwin then "clang"
+        else if final.useArocc then "arocc"
+        else if final.useZig then "zig"
+        else "gcc";
+
+      bintools = if final.useLLVM || final.useArocc || final.useZig || final.isDarwin then
+        "llvm"
+      else "gnu";
+
+      cxxlib =
+        /**/ if final.useLLVM || final.useArocc || final.useZig || final.isDarwin then "libcxx"
+        else "libstdcxx";
+
+      unwinderlib =
+        /**/ if final.useLLVM || final.useArocc || final.useZig then "libunwind"
+        else if final.isDarwin then "libunwind-system"
+        else "libgcc_s";
+
+      rtlib =
+        /**/ if final.useLLVM || final.useArocc || final.useZig || final.isDarwin then "compiler-rt"
+        else "libgcc";
+
+      # Choose what linker we wish to use by default. Someday we might also
+      # choose the C compiler, runtime library, C++ standard library, etc. in
+      # this way, nice and orthogonally, and deprecate `useLLVM`. But due to
+      # the monolithic GCC build we cannot actually make those choices
+      # independently, so we are just doing `linker` and keeping `useLLVM` for
+      # now.
+      linker =
+        /**/ if final.useLLVM then "lld"
+        else if final.isDarwin then "cctools"
+        # "bfd" and "gold" both come from GNU binutils. The existence of Gold
+        # is why we use the more obscure "bfd" and not "binutils" for this
+        # choice.
+        else "bfd";
+    };
+
     final = {
       # Prefer to parse `config` as it is strictly more informative.
       parsed = parse.mkSystemFromString (args.config or allArgs.system);
@@ -92,6 +136,8 @@ let
       isCompatible = _: throw "2022-05-23: isCompatible has been removed in favor of canExecute, refer to the 22.11 changelog for details";
       # Derived meta-data
       useLLVM = final.isFreeBSD || final.isOpenBSD;
+      useArocc = false;
+      useZig = false;
 
       libc =
         /**/ if final.isDarwin                then "libSystem"
@@ -112,19 +158,7 @@ let
         else if final.isNone                  then "newlib"
         # TODO(@Ericson2314) think more about other operating systems
         else                                     "native/impure";
-      # Choose what linker we wish to use by default. Someday we might also
-      # choose the C compiler, runtime library, C++ standard library, etc. in
-      # this way, nice and orthogonally, and deprecate `useLLVM`. But due to
-      # the monolithic GCC build we cannot actually make those choices
-      # independently, so we are just doing `linker` and keeping `useLLVM` for
-      # now.
-      linker =
-        /**/ if final.useLLVM or false      then "lld"
-        else if final.isDarwin              then "cctools"
-        # "bfd" and "gold" both come from GNU binutils. The existence of Gold
-        # is why we use the more obscure "bfd" and not "binutils" for this
-        # choice.
-        else                                     "bfd";
+
       # The standard lib directory name that non-nixpkgs binaries distributed
       # for this platform normally assume.
       libDir = if final.isLinux then
@@ -318,7 +352,7 @@ let
 
     }) // mapAttrs (n: v: v final.parsed) inspect.predicates
       // mapAttrs (n: v: v final.gcc.arch or "default") architectures.predicates
-      // args // {
+      // toolchain // args // {
         rust = rust // {
           # Once args.rustc.platform.target-family is deprecated and
           # removed, there will no longer be any need to modify any
@@ -430,6 +464,7 @@ let
          else throw message)
        true
        (final.parsed.abi.assertions or []);
+    assert (lib.listToAttrs (lib.map (key: lib.nameValuePair key final.${key}) (lib.attrNames toolchain))) == toolchain;
     final;
 
 in

pkgs/build-support/cc-wrapper/default.nix

@@ -120,8 +120,7 @@ let
 
   useGccForLibs = useCcForLibs
     && libcxx == null
-    && !targetPlatform.isDarwin
-    && !(targetPlatform.useLLVM or false)
+    && targetPlatform.rtlib == "libgcc"
     && !(targetPlatform.useAndroidPrebuilt or false)
     && !(targetPlatform.isiOS or false)
     && gccForLibs != null;
@@ -520,7 +519,7 @@ stdenvNoCC.mkDerivation {
     + optionalString (isClang
                       && targetPlatform.isLinux
                       && !(targetPlatform.useAndroidPrebuilt or false)
-                      && !(targetPlatform.useLLVM or false)
+                      && targetPlatform.rtlib == "libgcc"
                       && gccForLibs != null) (''
       echo "--gcc-toolchain=${gccForLibs}" >> $out/nix-support/cc-cflags
 

pkgs/by-name/al/alsa-lib/package.nix

@@ -25,7 +25,7 @@ stdenv.mkDerivation (finalAttrs: {
       # order to support apps with 32bit sound running on x86_64 architecture.
       ./alsa-plugin-conf-multilib.patch
     ]
-    ++ lib.optional (stdenv.hostPlatform.useLLVM or false)
+    ++ lib.optional (stdenv.hostPlatform.linker == "lld")
       # Fixes version script under LLVM, should be fixed in the next update.
       # Check if "pkgsLLVM.alsa-lib" builds on next version bump and remove this
       # if it succeeds.

pkgs/by-name/cl/cling/package.nix

@@ -27,7 +27,7 @@
 
   # Build with libc++ (LLVM) rather than stdlibc++ (GCC).
   # This is experimental and not all features work.
-  useLLVMLibcxx ? clangStdenv.hostPlatform.isDarwin,
+  useLLVMLibcxx ? clangStdenv.hostPlatform.cxxlib == "libcxx",
 }:
 
 let

pkgs/by-name/cy/cyrus_sasl/package.nix

@@ -74,7 +74,7 @@ stdenv.mkDerivation rec {
       "--enable-shared"
     ]
     ++ lib.optional enableLdap "--with-ldap=${openldap.dev}"
-    ++ lib.optionals (stdenv.targetPlatform.useLLVM or false) [
+    ++ lib.optionals (stdenv.hostPlatform.cc == "clang" && stdenv.hostPlatform.libc == "glibc") [
       "--disable-sample"
       "CFLAGS=-DTIME_WITH_SYS_TIME"
     ];

pkgs/by-name/el/elfutils/package.nix

@@ -63,7 +63,7 @@ stdenv.mkDerivation rec {
     ++ lib.optionals stdenv.hostPlatform.isMusl [ ./musl-error_h.patch ]
     # Prevent headers and binaries from colliding which results in an error.
     # https://sourceware.org/pipermail/elfutils-devel/2024q3/007281.html
-    ++ lib.optional (stdenv.targetPlatform.useLLVM or false) ./cxx-header-collision.patch;
+    ++ lib.optional (stdenv.targetPlatform.cxxlib == "libcxx") ./cxx-header-collision.patch;
 
   postPatch =
     ''
@@ -94,7 +94,7 @@ stdenv.mkDerivation rec {
       bzip2
     ]
     ++ lib.optional enableDebuginfod pkg-config
-    ++ lib.optional (stdenv.targetPlatform.useLLVM or false) autoreconfHook;
+    ++ lib.optional (stdenv.targetPlatform.cxxlib == "libcxx") autoreconfHook;
   buildInputs =
     [
       zlib
@@ -128,7 +128,7 @@ stdenv.mkDerivation rec {
       # Versioned symbols are nice to have, but we can do without.
       (lib.enableFeature (!stdenv.hostPlatform.isMicroBlaze) "symbol-versioning")
     ]
-    ++ lib.optional (stdenv.targetPlatform.useLLVM or false) "--disable-demangler"
+    ++ lib.optional (stdenv.targetPlatform.cxxlib == "libcxx") "--disable-demangler"
     ++ lib.optionals stdenv.cc.isClang [
       "CFLAGS=-Wno-unused-private-field"
       "CXXFLAGS=-Wno-unused-private-field"

pkgs/by-name/ke/kexec-tools/package.nix

@@ -19,13 +19,17 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-Z7GsUDqt5FpU2wvHkiiogwo11dT4PO6TLP8+eoGkqew=";
   };
 
-  patches = [
-    # Use ELFv2 ABI on ppc64be
-    (fetchpatch {
-      url = "https://raw.githubusercontent.com/void-linux/void-packages/6c1192cbf166698932030c2e3de71db1885a572d/srcpkgs/kexec-tools/patches/ppc64-elfv2.patch";
-      sha256 = "19wzfwb0azm932v0vhywv4221818qmlmvdfwpvvpfyw4hjsc2s1l";
-    })
-  ] ++ lib.optional (stdenv.hostPlatform.useLLVM or false) ./fix-purgatory-llvm-libunwind.patch;
+  patches =
+    [
+      # Use ELFv2 ABI on ppc64be
+      (fetchpatch {
+        url = "https://raw.githubusercontent.com/void-linux/void-packages/6c1192cbf166698932030c2e3de71db1885a572d/srcpkgs/kexec-tools/patches/ppc64-elfv2.patch";
+        sha256 = "19wzfwb0azm932v0vhywv4221818qmlmvdfwpvvpfyw4hjsc2s1l";
+      })
+    ]
+    ++ lib.optional (
+      stdenv.hostPlatform.unwinderlib == "libunwind"
+    ) ./fix-purgatory-llvm-libunwind.patch;
 
   hardeningDisable = [
     "format"

pkgs/by-name/li/libseccomp/package.nix

@@ -37,7 +37,7 @@ stdenv.mkDerivation rec {
     util-linuxMinimal
     which
   ];
-  doCheck = !(stdenv.targetPlatform.useLLVM or false);
+  doCheck = stdenv.targetPlatform.cc != "clang";
 
   # Hack to ensure that patchelf --shrink-rpath get rids of a $TMPDIR reference.
   preFixup = "rm -rfv src";

pkgs/by-name/ru/rutabaga_gfx/package.nix

@@ -45,7 +45,7 @@ stdenv.mkDerivation (finalAttrs: {
     ./link-cxx.patch
   ];
 
-  env = lib.optionalAttrs stdenv.hostPlatform.useLLVM {
+  env = lib.optionalAttrs (stdenv.hostPlatform.cxxlib == "libcxx" && !stdenv.hostPlatform.isDarwin) {
     USE_CLANG = true;
   };
 

pkgs/by-name/so/sourceHighlight/package.nix

@@ -62,11 +62,9 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ updateAutotoolsGnuConfigScriptsHook ];
   buildInputs =
     [ boost ]
-    ++ lib.optional (stdenv.targetPlatform.useLLVM or false) (
-      llvmPackages.compiler-rt.override {
-        doFakeLibgcc = true;
-      }
-    );
+    ++ lib.optional (
+      stdenv.hostPlatform.rtlib == "compiler-rt" && !stdenv.hostPlatform.isDarwin
+    ) llvmPackages.compiler-rt;
 
   configureFlags = [
     "--with-boost=${boost.out}"
@@ -92,7 +90,9 @@ stdenv.mkDerivation rec {
     maintainers = with maintainers; [ SuperSandro2000 ];
   };
 }
-// lib.optionalAttrs (stdenv.targetPlatform.useLLVM or false) {
-  # Force linking to "libgcc" so tests pass
-  NIX_CFLAGS_COMPILE = "-lgcc";
-}
+//
+  lib.optionalAttrs (stdenv.targetPlatform.rtlib == "compiler-rt" && !stdenv.hostPlatform.isDarwin)
+    {
+      # Force linking to "libgcc" so tests pass
+      NIX_CFLAGS_COMPILE = "-lgcc";
+    }

pkgs/development/compilers/llvm/common/clang/default.nix

@@ -198,7 +198,7 @@ let
     ninjaFlags = [ "docs-clang-man" ];
   }))
   // (lib.optionalAttrs (lib.versionAtLeast release_version "15") {
-    env = lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform && !stdenv.hostPlatform.useLLVM) {
+    env = lib.optionalAttrs (stdenv.buildPlatform != stdenv.hostPlatform && stdenv.hostPlatform.cc != "clang") {
       # The following warning is triggered with (at least) gcc >=
       # 12, but appears to occur only for cross compiles.
       NIX_CFLAGS_COMPILE = "-Wno-maybe-uninitialized";

pkgs/development/compilers/llvm/common/compiler-rt/default.nix

@@ -33,7 +33,6 @@
 
 let
 
-  useLLVM = stdenv.hostPlatform.useLLVM or false;
   bareMetal = stdenv.hostPlatform.parsed.kernel.name == "none";
   haveLibc = stdenv.cc.libc != null;
   # TODO: Make this account for GCC having libstdcxx, which will help
@@ -92,22 +91,22 @@ stdenv.mkDerivation {
     "-DCMAKE_ASM_COMPILER_TARGET=${stdenv.hostPlatform.config}"
   ] ++ lib.optionals (haveLibc && stdenv.hostPlatform.libc == "glibc") [
     "-DSANITIZER_COMMON_CFLAGS=-I${libxcrypt}/include"
-  ] ++ lib.optionals (useLLVM && haveLibc && stdenv.cc.libcxx == libcxx) [
+  ] ++ lib.optionals (stdenv.hostPlatform.cxxlib == "libcxx" && haveLibc && stdenv.cc.libcxx == libcxx && !stdenv.hostPlatform.isDarwin) [
     "-DSANITIZER_CXX_ABI=libcxxabi"
     "-DSANITIZER_CXX_ABI_LIBNAME=libcxxabi"
     "-DCOMPILER_RT_USE_BUILTINS_LIBRARY=ON"
   ] ++ lib.optionals ((!haveLibc || bareMetal || isMusl || isAarch64) && (lib.versions.major release_version == "13")) [
     "-DCOMPILER_RT_BUILD_LIBFUZZER=OFF"
-  ] ++ lib.optionals (useLLVM && haveLibc) [
+  ] ++ lib.optionals (stdenv.hostPlatform.rtlib == "compiler-rt" && haveLibc && !stdenv.hostPlatform.isDarwin) [
     "-DCOMPILER_RT_BUILD_SANITIZERS=ON"
   ] ++ lib.optionals (noSanitizers) [
     "-DCOMPILER_RT_BUILD_SANITIZERS=OFF"
-  ] ++ lib.optionals ((useLLVM && !haveLibcxx) || !haveLibc || bareMetal || isMusl || isDarwinStatic) [
+  ] ++ lib.optionals ((stdenv.hostPlatform.rtlib == "compiler-rt" && !haveLibcxx) || !haveLibc || bareMetal || isMusl || isDarwinStatic) [
     "-DCOMPILER_RT_BUILD_XRAY=OFF"
     "-DCOMPILER_RT_BUILD_LIBFUZZER=OFF"
     "-DCOMPILER_RT_BUILD_MEMPROF=OFF"
     "-DCOMPILER_RT_BUILD_ORC=OFF" # may be possible to build with musl if necessary
-  ] ++ lib.optionals (useLLVM && haveLibc) [
+  ] ++ lib.optionals (stdenv.hostPlatform.rtlib == "compiler-rt" && haveLibc && !stdenv.hostPlatform.isDarwin) [
     "-DCOMPILER_RT_BUILD_PROFILE=ON"
   ] ++ lib.optionals (!haveLibc || bareMetal) [
      "-DCOMPILER_RT_BUILD_PROFILE=OFF"
@@ -119,7 +118,7 @@ stdenv.mkDerivation {
     "-DCMAKE_SIZEOF_VOID_P=${toString (stdenv.hostPlatform.parsed.cpu.bits / 8)}"
   ] ++ lib.optionals (!haveLibc) [
     "-DCMAKE_C_FLAGS=-nodefaultlibs"
-  ] ++ lib.optionals (useLLVM) [
+  ] ++ lib.optionals (stdenv.hostPlatform.rtlib == "compiler-rt" && !stdenv.hostPlatform.isDarwin) [
     "-DCOMPILER_RT_BUILD_BUILTINS=ON"
     #https://stackoverflow.com/questions/53633705/cmake-the-c-compiler-is-not-able-to-compile-a-simple-test-program
     "-DCMAKE_TRY_COMPILE_TARGET_TYPE=STATIC_LIBRARY"
@@ -191,7 +190,7 @@ stdenv.mkDerivation {
   # Hack around weird upsream RPATH bug
   postInstall = lib.optionalString (stdenv.hostPlatform.isDarwin) ''
     ln -s "$out/lib"/*/* "$out/lib"
-  '' + lib.optionalString (useLLVM && stdenv.hostPlatform.isLinux) ''
+  '' + lib.optionalString (stdenv.hostPlatform.rtlib == "compiler-rt" && stdenv.hostPlatform.isLinux) ''
     ln -s $out/lib/*/clang_rt.crtbegin-*.o $out/lib/crtbegin.o
     ln -s $out/lib/*/clang_rt.crtend-*.o $out/lib/crtend.o
     # Note the history of crt{begin,end}S in previous versions of llvm in nixpkg: